Axial Skeleton and Vertebral Column Quiz

Axial Skeleton

• The skeleton is divided into two parts: appendicular and axial.
• Appendicular skeleton includes bones of the upper and lower limbs, and the pectoral and pelvic girdles.
• Axial skeleton includes the cranium, vertebral column, ribs, and sternum.

Vertebral Column

• Physically supports the skull and trunk.
• Allows movement of the skull and trunk.
• Protects the spinal cord.
• Absorbs stresses from walking, running, and lifting.
• Provides attachment for limbs, thoracic cage, and postural muscles.
• Consists of 33 vertebrae.
• Vertebral column has vertebral canal, and intervertebral discs connecting vertebrae together.

Cervical Vertebrae

• 7 cervical vertebrae located in the neck.
• Relatively small.
• Support the head and allow movement.
• C1 (atlas) and C2 (axis) have unique structures.
• Transverse foramina are unique to cervical vertebrae.

Thoracic Vertebrae

• 12 thoracic vertebrae in the chest.
• Each thoracic vertebra connects to ribs.
• The thoracic cage is a conical structure formed by the thoracic vertebrae, ribs, and sternum.
• Encloses the heart and lungs.

Lumbar Vertebrae

• 5 lumbar vertebrae in the lower back.
• Thick and stout bodies to support weight of the upper body.

Sacrum

• 5 sacral vertebrae fuse into a single bony plate, the sacrum.
• Posterior wall of the pelvic cavity. Protects pelvic organs.

Coccyx

• 4 or 5 tiny coccygeal vertebrae that fuse to form the coccyx.

Abnormal Spinal Curvatures

• Scoliosis: abnormal lateral deviation.
• Kyphosis: exaggerated thoracic curvature (hunchback).
• Lordosis: exaggerated lumbar curvature (swayback).

General Structure of a Vertebra

• Vertebral body: weight-bearing portion.
• Vertebral foramen: forms the vertebral canal.
• Vertebral arch: formed by the pedicles and laminae.
• Spinous process: prominent, palpable extension.
• Transverse processes: protrusions between lamina and pedicle for soft tissue attachment.

Intervertebral Discs

• Cartilaginous pads between the vertebral bodies.
• Absorb shock and help bind vertebrae together.
• Enhances spinal flexibility.
• 23 discs between vertebrae, first between C2-C3, and last between L5-S1.
• Excessive stress can lead to herniated discs.

Regional Characteristics of Vertebrae

• Cervical vertebrae (C1-C7): relatively small, support head and movement, contain transverse foramina.

Thoracic Cage

• Thoracic vertebrae, ribs, and sternum form protective conical cage, surrounding the heart and lungs.
• 12 pairs of ribs, the first 7 connect directly to the sternum via costal cartilage; Ribs 8-10 are false ribs, and 11-12 are floating ribs.

Sternum

• Breastbone, anterior to the heart.
• Divided into three regions: manubrium, body, and xiphoid process.
• Connects the ribs via costal cartilages to form the rib cage.

Ribs

• 12 pairs of ribs.
• Ribs 1-7 are true ribs, connected to the sternum by costal cartilage.
• Ribs 8-10 are false ribs, connected to the sternum by a common cartilage.
• Ribs 11 and 12 are floating ribs, with no sternal connection.

Skull and Cranial Cavity

• The skull: most complex part of the skeleton.
• Composed of 22 bones, sometimes more.
• Bones are connected by sutures
• Cranial fossae: depressions in the cranial base that match brain curves.
• Cranial bones form the cranial cavity, enclosing and protecting the brain.
• The skull has many cavities, including orbits and paranasal sinuses.

Cranial Cavities

• Cranial Cavity (largest cavity): about 1300mL, encloses the brain.
• Orbits (eye sockets).
• Nasal cavity.
• Paranasal sinuses.
• Oral cavity.
• Middle and Inner ear cavities.

Paranasal Sinuses

• Air-filled cavities within the skull bones.
• Connected to the nasal cavity, filled with mucus membrane and air..
• Lighten the skull's weight and give resonance to the voice.
• Named according to the bones they are in: frontal, maxillary, ethmoid, sphenoid.

Pelvic Girdle or Pelvis

• Bowl-shaped structure composed of sacrum, coccyx, and two hip bones.
• Supports the trunk on the lower limbs.
• Encloses pelvic viscera. Including the lower colon, urinary bladder, and reproductive organs.
• Greater pelvis: a broader upper region, forming walls of the lower abdominal cavity.
• Lesser pelvis: enclosed structure that contains and cushions pelvic viscera
• Pelvic inlet: opening circumscribed by the pelvic brim.

Pelvis (Differences between Sexes)

• Male pelvis is more robust or (heavier and thicker) than a female pelvis.
• Female pelvis is adapted for pregnancy and childbirth.

Pelvic Girdle or Pelvis Anatomy

• Pelvic inlet: entrance, formed by the pelvic brim.
• Pelvic outlet: exit, formed by the lower margin of the lesser pelvis.

Cranial Bones

• Frontal bone
• Parietal bone
• Temporal bone
• Occipital bone
• Sphenoid bone
• Ethmoid bone

Test your knowledge on the axial skeleton and the vertebral column. This quiz covers the structure, function, and unique features of cervical and thoracic vertebrae. Perfect for students learning about human anatomy.